Bag supporting and retaining means for a packing machine



y 1968 J. D. KEENAN, JR., ErAL 3,391,519

BAG SUPPORTING AND RETAINING MEANS FOR A PACKING MACHINE Filed Oct. 18,1965 7 Sheets-Sheet 1 INVENTORS: JOHN D. K EENAN, JR. WILLIAM E. SMITHJuly 9, 1968 J. D. KEENAN, JR.. ErAL 3,391,519

BAG SUPPORTING AND RETAINING MEANS FOR A PACKING MACHINE Filed Oct. 18,1965 7 Sheets-Sheet 2 log I I "'1 al'h IL90 l l J I 83 63 r 2r x04INVENTORS:

JOHN D. KEENA N, JR. WILL/AME. 6M1! Aggy ArrapMs'x s y 1968 J. o.KEENAN, JR., ETAL 3,391,519

BAG SUPPORTING AND RETAINING MEANS FOR A PACKING MACHINE 7 Sheets-Sheet3 Filed Oct. 18, 1965 INVENTORS: JOHN D. KEENAMJR. WILLIAM E. Smnl July9, 1968 K JR" ETAL 3,391,519

BAG SUP PORTING AND RETAINING MEANS FOR A PACKING MACHINE Filed Oct. 18,1965 7 Sheets-Sheet 4 INVENTORS. Jay/v D. K EENA JR WILLIAM E. SMITHgfiw 1 flrraelv VI July 9, 1968 J KEENAN, JR" ETAL 3,391,519

BAG SUPPORTING AND RETAINING MEANS FOR A PACKING MACHINE Filed Oct. 18,1965 7 Sheets-Sheet 5 on M T e NH EA m WM &- 7 KE m July 9, 1968 N, JR"ETAL 3,391,519

BAG SUPPORTING AND RETAINING MEANS FOR A PACKING MACHINE 7 Sheets-Sheet6 Filed Oct. 18, 1965 FIG. /3

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July 9, 1968 BAG SUPPORTING AND RETAINING MEANS FOR A PACKING MACHINEFiled Oct. 18. 1965 7 Sheets-Sheet 7 R. m M w W3 K5 Nu J w United StatesPatent 0 3,391,519 BAG SUPPORTING AND RETAENING MEANS FQR A PACKINGMACHINE John D. K enan, .lr., Qaldwell, and William E. Smith,

Upper Saddle River, N.J., assignors to Amsco Packaging Ildachinery,Inc., a corporation of New York Filed 0st. 13, 1965, Ser. No. 497,163 9Claims. (Cl. 53-189) ABSTRAQT 6F THE DISCLOSURE Platform supports bagbodies and table supports bag lips. Table continuously urged upwardly bya spring. Hydraulic device, independent of spring but responsive tomovement of table, moves platform upwardly at a rate faster than tablerate of movement.

This invention relates to packaging machines of the type in which bagsarranged in a stack are individually filled, through a filling opening,with merchandise to be packaged, and the filled bags then delivered to asealing apparatus which closes the filling opening. More particularly,the invention relates to the portion of the packaging machine whichsupports the stack of bags in flat condition with the uppermost bag inthe stack in position to be filled with merchandise and for lifting thestack as the bags are consumed to bring successive uppermost bags to thefilling position.

The bags with which the present invention is concerned are the typehaving a pair of opposed walls joined together along three sides andunconnected along the fourth side to define a filling opening or bagmouth. One of the walls is longer than the other to provide a lipextending from the bag mouth, the lip serving to facilitate opening ofthe mouth preparatory to the insertion of merchandise into the bag. Whenthe bags are stacked, it will be appreciated that the height of thestack of bag lips is less than the height of the bag bodies inasmch aseach lip includes only a single ply of material whereas each bag bodyincludes two plies of material. As a result, in any stack comprising asubstantial number of bags, 21 hump is formed at the top of the stack inthe region of the bag mouth of the uppermost bag. This hump is desirablesince it aids in opening the bag by causing the lip and lower wall ofthe bag to be bent downwardly away from the free edge of the upper wall.Consequently, the adhesion between the walls is broken,

and the edge of the upper wall is exposed so that a blast of air can bedirected beneath it and lift the entire upper wall off the lower wall ofthe bag.

The stack dwindles as bags are filled and removed from it, and the humpdiminishes as well until it is almost imperceptible even though arelatively large number of bags still remain in the stack. The reason isthat the bag walls are so thin, particularly the walls of so-calledplastic bags, that a great number of bags are required to produce a humpwhich is of any help in opening the bag. To overcome this difficulty,the present invention supports the single-ply portions of the bags,i.e., the lips, and the two-ply portions of the bags, i.e., the bagbodies, on two separate carriers which rise at different rates of speedas the bags are used.

Specifically, the carrier supporting the bag bodies moves upwardly at afaster rate than the other carrier. In this way, the top level of thebag bodies is maintained substantially higher than the top level of thelips throughout the life of the stack of bags, and a hump is provided atthe bag mouth of every bag, even the last bag in the stack.

A two-part bag support has been suggested in the past,

3,391,519 Patented July 9, 1968 but has presented certain problems. Thechief difficulty resides in the fact that a single spring has beenemployed to raise both carriers. An abutment is provided, fixed to themachine frame, against which the top of the stack of bag lips is pressedby the spring. The abutment, therefore, limits the upward movement ofthe carriers and causes the uppermost bag in the stack to be located inproper position for filling with merchandise. The spring must of coursebe strong enough to lift both carriers supporting a full complement ofbags. As the bags are consumed and the weight of the stack decreases,the spring presses the bag lips against the abutment with a constantlyincreasing force. Ultimately, the lips become clamped so tightly betweenthe carrier which supports the lips and the abutment that the bags havea tendency to tear as they are removed from the stack after beingfilled.

It is a general object of the present invention to provide a two-carriersupport for a stack of bags which overcomes the problem outlined above,as well as other problems.

It is a more specific object of the invention to provide a two-carriersupport for a stack of bags wherein each of the carriers is raised by anindependent lifting means.

It is another object of the invention to provide a means for correlatingthe operation of the two independent lifting means so that the carrierwhich supports the bag bodies moves up more rapidly than the carrier forthe bag lips.

A feature of the invention involves the provisionof special retainingmeans for maintaining all the bags in an orderly stack, but for readilyreleasing each bag when it comes to the top of the stack and is filledwith merchandise.

In brief, the preferred embodiment of the invention includes a tablestructure for supporting the bag lips, and a separate platform structurefor carrying the bag bodies. A lifting means, such as a spring,continuously urges the table structure upwardly, and an independentlifting means, such as an hydraulic piston-cylinder device, is adaptedto raise the platform structure. A valve for controlling the flow ofhydraulic fluid to the piston-cylinder device is mounted on the platformstructure, and is arranged to be actuated by one arm of a leverpivotally mounted between its ends on the table structure. The other armof the lever engages an abutment fixed to the machine. Consequently, asthe table structure rises, the lever pivots about the abutment andactuates the hydraulic valve causing the platform structure to riseuntil the valve moves out of contact with the lever. Since the point onthe lever which contacts the valve is spaced further from the abutmentthan the point at which the lever is mounted on the table structure, theformer rises faster than the latter and hence the platform structuresupporting the bag bodies rises faster than the table structuresupporting the bag lips.

Inasmuch as the lifting spring need be strong enough to raise only thetable structure and the bag lips, the great majority of the weight ofthe bags being lifted by the piston-cylinder device, the force withwhich the spring presses the lips against an abutment located above thetable does not vary appreciably as the stack is consumed, and hence thebags do not become tightly clamped between the table and the abutment.Furthermore, the abutment i preferably a roller having an attenuatededge, thus contributing to the ease of removing bags from the stack.

The special retaining means for the stack preferably include a U-shapedwire, or wicket, the vertical arms of which extend through aligned holesin all the bag lips. The arms terminate at about the level of theuppermost lip in the stack, and a clip is spring biased toward the upperend of each arm to minimize the possibility of accidental removal of thebags from the wicket. The clips, however, do not prevent removal of thebags from the stack as the bags are filled.

Additional features and advantages of the invention will be apparentfrom the following detailed description in which reference is made tothe accompanying drawings.

In the drawings:

FIG. 1 is a perspective view of a stack of bags on a support, theuppermost bag of the stack about to be filled with an article ofmerchandise;

FIG. 2 is an elevational view of a bag supporting and raising meansaccording to the present invention, supporting a full stack of bags;

FIG. 3 is a horizontal cross-sectional view taken along line 3-3 of FIG.2;

FIG. 4 is a horizontal cross-sectional view taken along line 44 of FIG.2;

FIG. 5 is a view similar to FIG. 6 after about one-half of the stack ofbags has been consumed;

FIG. 6 is a view of some of the parts in the lower portion of FIG. 2when the bag supporting means is in position to be loaded with a newstack of bags;

FIG. 7 is a schematic view of the hydraulic circuit for moving theplatform structure of the bag supporting means, the hydraulic valvebeing shown closed;

FIG. 8 is a schematic view of the hydraulic valve of FIG. 7 in openposition;

FIGS. 911 are schematic views showing the relationship between the tableand the platform with different numbers of bags resting upon them;

FIG. 12 is an elevational view along the line 12-12 of FIG. 2;

FIG. 13 is an underneath view taken along the line 1313 of FIG. 12;

FIG. 14 is a vertical cross-sectional view taken along line 14-14 ofFIG. 12;

FIG. 15 is a vertical cross-sectional view taken along line 1515 of FIG.12.

Referring to FIG. 1, a stack of bags 30 is shown, each bag comprising anupper wall 31 and a lower wall 32, the lower wall being elongated toform a lip 33 adjacent to the mouth of the bag. Each bag lip is providedwith a pair of spaced apart holes aligned with corresponding holes inthe other bag lips, and the two vertical arms of a U-shaped wireretainer or wicket 34 extend through the two sets of aligned holes. (Theholes 35 in the bag lips are best shown in FIGS. 12 and 15.) At thebeginning of each bag-filling cycle, air is blown through a tube 36(also shown in FIGS. 2, l2, and 14) toward the mouth of the uppermostbag in the stack in order to balloon the upper wall 31 upwardly awayfrom the lower wall 32 (FIG. 1). Then, a pair of channel-shaped arms(not shown) are pivoted into the air-filled bag against the inner sideedges of the bag in order to hold it open, and one of a series of pushermembers 37, carried by a pair of endless chains, slides an article ofmerchandise 40, such as a folded shirt, along a support surface 39 (FIG.2) into the open bag. After the article 40 reaches the edge of the bagopposite the bag mouth, continued movement of the pusher member causesthe bag to move ofi the top of the stack 30 to a delivery point fromwhich it is transported to a bag sealing station (not shown).

A stack of bags of the type described, containing .a substantial numberof bags, is inherently formed at its top with a hump 41 (see FIGS. 1, 9,10, 14, and 15) in the region where the single-ply lip portions 33 ofthe bags join the double-ply body portions 31, 32 of the bags. It shouldbe mentioned that in the drawings the thickness of the bag walls hasbeen exaggerated for the sake of clarity, and hence each stack actuallycontains many more bags than are shown. As a result of the hump 41, thelower bag wall 32 of the uppermost bag in the stack is bent away fromthe upper bag wall 31 in the region of the bag mouth (see for exampleFIG. 14), leaving the inner surface of the upper wall 31 adjacent to theedge 42 exposed. Thus, when air is blown from tube 36 toward the bagmouth it flows beneath the edge 42 and lifts the bag wall 31 to theposition shown in dobdash lines in FIG. 14.

Referring to FIGS. 1 and 2, the stack of bags 39 rests on a two-partsupporting and lifting mechanism including a platform 43 carrying thebag bodies, and a table 44 carrying the bag lips. The platform 43 ismounted on the upper ends of a pair of vertical rods 45, and the table44 is mounted on the upper ends of a pair of vertical rods 46. The rods45 and 46 are guided in their vertical movements by a stationaryframework comprising a pair of spaced-apart vertical plates 47 (see FIG.3), secured to the machine frame 50 by bolts 51, and upper and lowerhorizontal guide plates 52 secured to the top and bottom edges,respectively, of the plates 47. Four bushing-lined holes 53 are providedin each of the guide plates 52 for slidably accommodating one each ofthe four rods 45 and 46.

Interconnecting the lower ends of the table rods 46 is a block 54 (seeFIGS. 2 and 4) having a stud 55 projecting from it. The lower end of acable 56 is secured to the stud 55, and the cable extends upwardly andis wound around a reel 57 (FIGS. 2 and 3) rotatably mounted on ahorizontal shaft 58 extending between the plates 47. The reel 57 is, inwell-known fashion, spring biased to rotate in the direction tending towind up the cable. Consequently, the spring biased reel serves toconstantly urge the rods 46, table 44, and the bag lips 33 upwardly.This upward movement is limited by an abutment, in the form of a roller61 (FIGS. 1 and 2) located above the table 44 and against which the baglips are pressed. The roller 61 will be described in more detail below.

Directly above the block 54, the table rods 46 pass through a plate 62extending between the rods, the plate being fixed with respect to therods by means of collars 63 fastened to each rod above and below theplate 62. A lever 64 is pivotally secured, at about its midpoint, to oneend of the plate 62 by means of a horizontal stud 65. Thus, the lever 64is arranged to move with the rods 46. An abutment in the form of astationary pin 66 (FIGS. 2 and 4) is disposed in the path of upwardmovement of one end of the lever 64. The pin 66 is located in the lowerend of a frame extension 67 depending from one of the plates 47 andsecured to the latter by means of screws 68. The screws 68 pass throughan elongated slot 71 in the extension 67 which allows the position ofthe extension and hence the pin 66 to be adjusted. It will beappreciated that as the table rods 46 rise, the lever 64 pivots in acounterclockwise direction about the pin 66. For a reason to bedescribed below, rotation of the lever in a clockwise direction aboutthe stud 65 is limited by a set screw 72. The set screw is carried by aplate 73 carried by the rods 46 above the plate 62, the plate 73 beingfixed to the rods 46 by means of collars 74 fastened to each rod aboveand below the plate 73.

The lower ends of the platform rods 45 are interconnected (FIGS. 2 and4) by a block 75 and a plate 76 arranged below the block, the platebeing formed with a narrow, horizontally projecting arm 77 through whichthe movement of a piston '79 (FIG. 7) within an hydraulic cylinder 78 istransmitted to the rods 45. The lower end of the piston rod 81 carries ayoke 82 which straddles the arm 77 and is fixed to it by a pin 83. Theupper end of the cylinder 78 is secured to a stationary horizontalmember 84 (FIG. 3) mounted between the plates 47. The rods 45 passthrough a plate 85 located above the block 75, the plate being fixed tothe rods by means of collars 86 fastened to each rod 45 above and belowthe plate. Secured to one edge of the plate 85 is a control valve 87forming part of the hydraulic system for lifting the rods 45 and hencethe platform 43. The valve 87, which moves with the rods 45, is locateddirectly above a point on the lever 64 which is on the side of the pivotstud 65 opposite to the stationary pin 66. The operating pin 88 of thevalve 87 projects downwardly toward the lever 64, and is actuated bymovement of the lever 64 via a short lever 89 arranged between the valveand lever 64 and pivotally mounted at one of its ends to a bracket 90carried by the valve.

In addition to the piston-cylinder device 78, 81, and the valve 87, thehydraulic system includes (see FIGS. 2-4 and 7) a pair of reservoircylinders 93 and 94 mounted on stationary brackets 95 fixed to the outerface of one of the plates 47. Each of the reservoir cylinders isprovided with a plunger 97 separating the liquid space 98 within thecylinder from the air space 99 above it. Flexible conduits, which forthe sake of clarity are represented by single solid lines in FIG. 2interconnect the parts of the hydraulic system. Thus, a conduit 182connects the space above the piston 79 within cylinder 78 to the fluidspace 98 within reservoir cylinder 94, a conduit 183 connects the spacebelow the piston 79 within cylinder 78 to the control valve 87, and aconduit 184 connects the control valve to the fiuid space 98 withinreservoir cylinder 93. Therefore, when the control valve 87 is open, asshown in FIG. 8, the cylinders 78 and 93 are in fluid communication, andwhen the valve 8'7 is closed, as shown in FIG. 7, this communication isblocked.

The hydraulic system just described is pneumatically actuated, the fiowof air to the system being controlled by a four-way pneumatic valve 185mounted on the outer face of one of the plates 47. One port 196 of thevalve 105 communicates with a source of air under pressure (not shown),and another port 187 is open to the atmosphere. The remaining two ports188 and 109 of the valve communicate with the air spaces 99 within thecylinders 93 and 94, respectively, via the air lines 112. With the valvemember 105a in the position shown in FIG. 7, the air space 99 ofcylinder 93 is pressurized and the air space of cylinder 94 exhausted.Consequently, when control valve 87 is open, the piston '79 will risewithin the cylinder 78 and lift the rods 45 and platform 43 with it.When the valve member 105a is rotated 90 in either direction, by meansof handle 113, the cylinder 93 is exhausted and cylinder 94 ispressurized. Hence, when the control valve 87 is open, the piston 79will descend and move the platform 43 down with it.

To explain the operation of the illustrative bag supporting and liftingmechanism described above, assume first that the apparatus is in theposition shown in FIGS. 2 and 9. In this position, a full stack of bags30 is in place on the mechanism, the lips 33 of the bags being heldbetween the table 44 and roller 61. As illustrated, the full stack ofbags contains such a large number of bags that if it were placed on alevel surface the natural hump formed would be greater than desirable.Hence, the platform 43 is initially lower than the table 44 to reducethe hump 41 to desired size. The lever 64 is in contact with the pin 66,and the valve 87, carried by the platform rods 45, is located just farenough above the lever 64 to permit the pin 88 to assume its lowerposition wherein the valve 87 is closed, as shown in FIG. 7. Inaddition, the valve 105 is arranged as shown in FIG. 7, wherein thereservoir cylinder 93 is pressurized and the cylinder 94 is exhausted.

As bags are filled with articles of merchandise 40, and removed from thestack 30, the height of the stack of lips 33 diminishes, and thespring-biased reel 57, by means of cable 56, lifts the rods 46 and table44 to maintain the lips 33 in contact with theroller 61. As a result ofthe upward movement of the rods 46, the lever 64 moves upwardly andpivots in a counterclockwise direction about the pin 66. The lever 64thus pushes the pin 88 of the valve 87 upwardly, via the short lever 89,and opens the valve as shown in FIG. 8. In consequence, hydraulic fluidunder pressure flows from the reservoir cylinder 93 (FIG. 7) throughconduit 104, valve 87, and conduit 103 into the cylinder 78 below thepiston 79, thus moving the piston 79 upwardly. The displaced fluid abovethe piston 79 flows through the conduit 102 into the reservoir cylinder94. Upward movement of the piston 79 is transmitted to the rods 45 bymeans of the piston rod 81 and plate 76, whereby the platform 43,carrying the stack of two-ply bag bodies, rises. The rods 45 andplatform 43 continue to rise until the valve 87 moves far enough abovelever 64 to permit the valve to close, under the influence of the valvespring 114, whereupon upward movement of the platform stops. Thereafter,as the stack of bags 38 continues to be consumed, the table rods 46 risecausing additional upward pivotal movement of the lever 64 about pin 66thereby opening the valve 87 again to effect a rise in the platform 43.

Since the valve 87 is spaced farther from the pin 66 than the stud 65,by means of which the lever 64 is pivotally mounted to the table rods46, the point on the lever which aotuates the valve 87 will rise at afaster rate, i.e., will move through a longer an in a given period oftime, than the stud 65. Hence, the platform 43 will rise at a fasterrate than the table 44, the difference in the rates depending, ofcourse, upon the relationship between the pin 66-stud 65 spacing the pin66valve 87 spacing. As a result, by the time the stack of bags has beendepleted to some extend, as shown in FIG. 10, the table 44 and platform43 become disposed at the same level. In this condition of the table andplatform, the lever 64 and its associated parts are in the positionshown in FIG. 5. By the time the stack is almost entirely consumed, asshown in FIG. 11, the platform 43 has risen above the level of the table44 in order to provide the hump 41 for the few remaining bags.

When all the bags are gone, and it is desired to reload the bagsupporting and lifting device, the valve member 105a is rotated 90 fromthe position shown in FIG. 7 by means of the handle 113 in order toexhaust the reservoir cylinder 93 and pressurize the cylinder 94.Consequently, pressure is applied above the piston 79 causing thepiston, and hence the rods 45, to move downwardly. The downward movementof the rods 45 causes the short lever 89 to press against the lever 64and assume the position shown in FIG. 6, wherein the upper face of theshort lever engages the lower face of the bracket 90. The short leverthereby protects the valve 87, since if the short lever were not presentthe downward movement of the rods 45 would be transmitted to the lever64 via the valve pin 88. Furthermore, the short lever holds the pin 88in its upper position, with the result that the valve 87 remains openconstantly and the lever 64 is pivoted downwardly, or in a clockwisedirection, about the pin 66, pulling the table rods 46 down with it. Theparts move downwardly until the piston 79 completes its downward strokewithin the cylinder 78. This represents a position of the parts lowerthan that shown in FIG. 2, in order to permit a new stack of bag lips 33to be conveniently placed upon the table 44 without obstruction from theroller 61. As the parts pass the position of FIG. 2 during theirdownward movement, the lever 64 comes into engagement with the set screw72, as shown in FIG. 6. The set screw prevents further clockwiserotation of the lever 64 and hence the latter moves downwardly away fromthe pin 66. As a result, the relative levels of the table 44 andplatform 43 remain constant throughout the movement of the par-ts afterthe lever 64 moves out of contact with the pin 66. The table andplatform are thus in the most desirable relative positions for receivinga new stack of bags when the parts come to a halt at the termination ofthe stroke of the piston 79. After the new stack of bags is in place,the pneumatic valve is returned to the condition shown in FIG. 7, andthe parts rise until they reach the position shown in FIG. 2; the bagfilling operation can then be resumed.

The means for retaining the bags in an orderly stack as they wait to befilled, and for readily releasing each bag when its turn to be filledarrives, will be described with reference to FIGS. 1, 2, and 12-15. Thebags are supplied to the bag user mounted on a U-shaped wire holder orwicket 34, referred to above, the vertical arms of the wicket extendingthrough two sets of aligned holes 35 in the bag lips 33. After a newstack 30 is laid on the platform 43 and table 44, the horizontal crossbar of the wicket is snapped into a groove in a portion of the machineframe 50 (see FIGS. 2 and behind a resilient clip 115. The vertical armsof the wicket pass through, and are supported by, two of a series ofnotches 116 provided along one edge of a plate 117 forming part of thetable 44. Provision of the plurality of notches 116 permits the plate117 to accommodate wickets of varying widths. During the operation ofthe apparatus, the wicket 34 remains stationary, and the plate 117 andbag lips 33 slide upwardly along the vertical arms of the wicket.

The last portion of the surface 39 (FIGS. 2 and 14) over which themerchandise 40 slides before it is delivered to a waiting bag is definedby a plate 118 mounted on the machine frame 50 'by means of screws 119(FIGS. 12 and 13). The roller 61 is mounted below the plate 118 by meansof a block 122 (FIGS. 12-14) secured to the under surface of the plateby a screw 123. The roller is located within a slot formed in the block122 and is rotatably carried by a shaft 124 extending across the slot.The roller 61 is attenuated so that only a relatively sharp edge engagesthe upper lip 33 of the stack. Consequently, although the roller servesto limit the upward movement of the stack under the influence of thetable 44, it offers very little resistance to the horizontal movement ofthe uppermost bag off the stack after it has been filled. The endportions of the shaft 124 extend beyond the block 122, and pass throughopenings in a pair of ears 125 (FIGS. 1, 12, and 14) projecting upwardlyfrom a curved baths 126. The baffle is adapted to rest upon the top ofthe stack of bag lips 33, and in this position it curves downwardly infront of the air tube 36 and directs the air toward the edge 42 of theuppermost bag in the stack.

The bag lips 33 are maintained in fiat condition by means of a pair ofhorizontal, resiliently-biased fingers 127 supported beneath the plate118, one end of each finger being positioned directly over the upper endof one of the arms of the wicket 34. The other end of each finger islocated within a slot formed in the lower face of a block 128, and ispivotally mounted on a pin 129 extending across the slot and having its;ends supported by the block 128. Each block 128 is slidably mounted on apair of parallel rods 132 spaced slightly below, and extending along thelength of, the plate 118, the rods passing through holes in the blocks128. The rods 132 are held in place by means of supports 133 fastened tothe under face of the plate 118 by means of screws 134. The block 128and the fingers 127 carried by them can be adjusted along the length ofthe rods 132 to position the fingers for cooperation with the arms ofdifferent sized wickets 34. To aid the positioning of the fingers, theunder face of the plate 118 is provided with a series of smalldepressions 135 (FIG. 13), and a spring-backed ball 136 (FIG. 15)projects from the upper face of each block 128 and cooperates with thedepressions 135.

Extending vertically through a threaded hole in each finger 127 is athreaded pin 137, the pin projecting above the finger and into a hole inthe block 128. A compression spring 138 within the hole surrounds thepin 137 and extends between the top wall of the hole and the uppersurface of the finger 127, thereby constantly urging the fingerdownwardly toward the upper end of the wicket arm directly below thefinger. Thus, the fingers 127, under the influence of their respectivesprings 138, serve to press down against the upper lip 33 in the stackand keep it flat, but due to the relatively long moment arm between eachof the pins 129 and the arms of the wicket 34, the fingers 127 offervery little resistance to the removal of the lips 33 in a horizontaldirection from beneath the fingers.

An electrical contact 139 (FIGS. 1 and 14) may be pro vided on the table44, preferably in a recess in the upper surface of the table so that itis flush with the table top. The contact 139 is insulated from themachine frame and is in vertical alignment with the roller 61, which isin electrical contact with the machine frame. By means of suitablecircuitry, not shown, connected between the machine frame and thecontact 139, the machine can be automatically shut off when the last bagin the stack is removed from the table 44 and the roller 61 comes intoengagement with the con-tact 139.

The invention has been shown and described in preferred form only, andby way of example, and many variations may be made in the inventionwhich will still be comprised within its spirit. It is understood,therefore, that the invention is not limited to any specific form orembodiment except insofar as such limitations are included in theappended claims.

What is claimed is:

1. In a packaging machine for filling bags of the type having a pair ofopposed walls, one wall being longer than the other to provide a lipextending from the mouth of the bag; means for supporting a stack ofbags in fiat condition with the uppermost bag in the stack in positionto be filled with merchandise to be packaged and for lifting the stackas the bags are consumed to bring successive uppermost bags to thefilling position, said means comprising a table structure for supportingthe single-ply lip portions of the bags and a platform structure forsupporting the two-ply portions of the bags, means for continuouslyurging said table structure upwardly, means independent of saidtable-urging means adapted to raise said platform, and means forcorrelating the movements of said table structure and platform structureso that said platform rises at a faster rate than said table.

2. In a packaging machine, the elements defined in claim 1 wherein saidlast-named means comprises mechanism operatively interposed between saidtable structure and said platform-raising means and controlling thelatter in response to table movement.

3. In a packaging machine, the elements defined in claim 1 wherein saidplatform-raising means includes a control device mounted on saidplatform structure, and said movement-correlating means includesmechanism operatively interposed between said table structure and saidcontrol device and actuating the latter in response to table movement.

4. In a packaging machine, the elements defined in claim 3 wherein saidplatform-raising means includes an hydraulically-actuated device, andsaid control device is a valve for controlling fluid flow to saiddevice.

5. In a packaging machine, the elements defined in claim 4 wherein saidhydraulically-actuated device is a piston-cylinder device arrangedbetween said platform structure and the machine frame.

6. In a packaging machine, the elements defined in claim 5 including ahydraulic circuit connected to said cylinder on each side of saidpiston, one of said circuits including said valve, and means forpressurizing said one circuit and relieving the other when it is desiredto raise said platform and for relieving said one circuit andpressuiizing the other when it is desired to lower said platform.

7. In a packaging machine, the elements defined in claim 3 wherein saidmechanism comprises a lever arranged to pivot upwardly about a pointfixed with respect to the machine frame as said table structure rises,said control device being arranged to be acted upon by a portion of saidlever spaced farther from said fixed point than said table structure,whereby the lever portion which actuates said control device movesupwardly at a faster rate than said table structure.

8. In a packaging machine, the elements defined in claim 3 wherein saidmechanism comprises a lever pivotally mounted at a point intermediateits ends to said table structure, and relatively fixed means forpreventing the upward movement of a point on said lever spaced from saidintermediate point, whereby as said table structure rises said leverpivots upwardly about said fixed means, said control device beingarranged to be acted upon by the portion of the lever on the side ofsaid intermediate point opposite said fixed means.

9. In a packaging machine, the elements defined in claim 8 wherein saidfixed means is an abutment mounted on the machine frame in the path ofupward movement of said lever, and including means for limiting thedown- Ward rotation of said lever, and means for moving said ReferencesCited UNITED STATES PATENTS 3,174,260 3/1965 Saumsiegle et a1. 531893,206,913 9/1965 Fleigher et al. 53189 3,330,093 7/1967 Schorer 53189TRAVIS S. MCGEHEE, Primary Examiner.

platform structure downwardly preparatory to placing a 15 E. F. DESMOND,Assistant Examiner.

